Liquefied natural gas, referred to in abbreviated form as “LNG,” is a natural gas which has been cooled to a temperature of approximately −162 degrees Celsius with a pressure of up to approximately 25 kPa (4 psig) and has thereby taken on a liquid state. Natural gas (NG) is primarily composed of methane, and can include ethane, propane, and heavy hydrocarbon components such as butanes, pentanes, hexanes, benzene, toluene, ethylbenzene, and xylenes. Many natural gas sources are located a significant distance away from the end-consumers. One cost-effective method of transporting natural gas over long distances is to liquefy the natural gas and to transport it in tanker ships, also known as LNG-tankers. The LNG is transformed back into gaseous natural gas at the destination.
In a typical liquefaction process a compressor is used to deliver pressurized mixed refrigerant (MR) to a cold box, which in turn is used to cool a feedstock, such as a natural gas, to form a liquefied gas. Cryogenic refrigeration systems, which are used in the production of LNG, require a significant amount of power to operate, and they tend to have a high capital cost. Accordingly, there is a need for methods and devices for increasing the efficiency of cryogenic refrigeration systems that are used in the production of LNG.